/Engine/Source/Runtime/Engine/Classes/Components/AudioComponent.h
Retrieves the current-time amplitude envelope data of the sounds playing on the audio component. Envelope data is not averaged or interpolated. Instead an array of data with all playing sound waves with cooked data is returned. Returns true if there is data and the audio component is playing.
bool GetCookedEnvelopeDataForAllPlayingSounds ( [TArray](API\Runtime\Core\Containers\TArray)< [FSoundWaveEnvelopeDataPerSound](API\Runtime\Engine\Sound\FSoundWaveEnvelopeDataPerSound) > & OutEnvelopeData )